Aggressive forms of adult T-cell leukemia (ATL) respond poorly to conventional anticancer chemotherapy, and new lead compounds are required for the development of drugs to treat this fatal disease. Recently, we developed ATL cell-selective proliferation inhibitors based on a tetrahydrotetramethylnaphthalene (TMN) skeleton 1, and here we report the design and synthesis of silicon analogs of TMN derivatives. Among them, compound 13 showed the ...